1. Field of the Invention
The present invention relates generally to fluid-filled vibration damping devices capable of exhibiting damping effect on the basis of flow action of non-compressible fluid sealed therein, and more particularly to a fluid-filled vibration damping device suitably applicable to engine mounts or other mounts for use in automotive vehicles, for example.
2. Description of the Related Art
Vibration-damping devices, typically including a first and a second mounting member elastically connected via a rubber elastic body, have been widely used in a variety of fields as vibration damping couplings or mounts which are interposed between two members of a vibration system. As one type of such vibration damping devices, there have been proposed a fluid-filled vibration damping device that is of construction further includes: a pressure-receiving chamber whose wall is partially defined by the rubber elastic body and undergoes fluid pressure fluctuation upon application of vibration between the first and second mounting members; an equilibrium chamber whose wall is partially defined by a flexible layer and permits a volumetric change thereof as a result of deformation of the flexible layer; a partition member assembled with the second mounting member so as to form on the opposite sides thereof the pressure-receiving chamber and the equilibrium chamber each having non-compressible fluid sealed therein; and an orifice passage for permitting a fluid communication between the pressure receiving chamber and the equilibrium chamber. Typical examples of such a fluid-filled vibration-damping device are disclosed in JP-A-7-243472 and JP-A-2001-165231, for example.
The fluid-filled vibration damping device of this construction is capable of exhibiting vibration damping effect on the basis of resonance or other flow action of the non-compressible fluid sealed therein, thereby readily affording low dynamic spring action and high attenuation action in the tuning frequency range at levels not achieved simply by damping action of a rubber elastic body. For this advantage, the fluid-filled vibration-damping device has been studied to apply to automotive vibration damping devices in which high levels of damping performance are required in certain specific frequency ranges.
Extensive researches conducted by the inventor has revealed that the fluid filled vibration damping device of conventional design may suffer from noises or vibrations induced therein when an impulsively large vibrational load is applied between the first and second mounting members.